ARLINGTON — Major League Baseball recorded its first victory in the Biogenesis investigation yesterday, and it was the equivalent of the Yankees blowing out the Red Sox on Opening Day — Ryan Braun, MLB’s longtime nemesis, agreed to be suspended for the duration of the 2013 season.

Braun, who defeated baseball last year in an appeal of a positive urine test, negotiated what amounts to a 65-game suspension — and the postseason, if the Brewers (41-56 entering last night’s game) made a miracle run into the playoffs — for his association with Biogenesis, the now-shuttered South Florida drug clinic, and its owner Anthony Bosch, who has been helping MLB’s investigation.

Baseball’s evidence on beleaguered Yankees third baseman Alex Rodriguez’s involvement with Bosch and Biogenesis is said by sources to dwarf the information obtained on Braun.

“As I have acknowledged in the past, I am not perfect,” Braun said, in part, in a statement released by MLB. “I realize now that I have made some mistakes. I am willing to accept the consequences of those actions.”

It’s no coincidence that the term “illegal performance-enhancing drugs” doesn’t appear in Braun’s statement. Baseball officials, satisfied with the length of Braun’s sentence and the implication of his statement, opted not to push this issue. By accepting a penalty greater than 50 games, the standard for a first-time offender, Braun essentially admitted to his prior offense.

“We commend Ryan Braun for taking responsibility for his past actions,” said Rob Manfred, MLB’s executive vice president of economics and league affairs. “We all agree that it is in the best interests of the game to resolve this matter. When Ryan returns, we look forward to him making positive contributions to Major League Baseball, both on and off the field.”

Braun’s contract called for him to make $8.5 million this year, so he’ll lose out on about $3.4 million. He’s signed with Milwaukee through 2020 with a mutual option for 2021.

Said Players Association executive director Michael Weiner: “I am deeply gratified to see Ryan taking this bold step. It vindicates the rights of all players under the Joint Drug Program. It is good for the game that Ryan will return soon to continue his great work both on and off the field.”

The news flashed on the scoreboard here at Rangers Ballpark before the Yankees opened their three-game series here against Texas.

“Any time you’re sitting around here talking about this kind of stuff, it’s not fun. It’s not good for the game,” Derek Jeter said. “It shows what they’re trying to do is working.”

Said Andy Pettitte, who admitted in 2007 to his usage of human growth hormone: “You make a mistake, you move forward. The biggest thing is to mean what you say. You move forward. Hopefully, obviously, [Braun is] a young player. He’s got a long career ahead of him. You put this in your rearview mirror and he doesn’t do anything like this again, obviously.”

The veteran Yankees acknowledged that, with Braun knocked out by MLB, A-Rod could follow. Braun opted to not fight baseball. A-Rod could still appeal his ruling, or like Braun, he could negotiate a settlement. Yankees catcher Francisco Cervelli also is a target of the investigation.

“Everybody’s waiting to see what happens,” Pettitte said. “You hope that guys are obviously involved with our team, nothing comes down, nothing happens in a case where someone would be suspended. Those are our teammates, you know? We want them back, and we wish nothing but the best for them.”

Asked specifically whether he would stand by A-Rod if he gets suspended, Pettitte said, “We’re going to back him up. We’re his teammates. There’s no doubt. But if he did something wrong, he’s going to be punished for it. But I’ll still back him up. I’m still going to love him. Because I built a relationship with him. He’s a teammate of mine. So you just wish nothing but the best for him.

Added Mariano Rivera about A-Rod: “Yeah, I have to support him. He’s my teammate. He’s my brother. Definitely. I don’t sense if he did or if he didn’t do it. But if it happens, I can’t throw him in the street. He’s still my brother.”